lock access to model dictionaries during encode

* Identity Model and Properties Model have access to their aliases and tags dictionary wrapped in a lock. However, this lock was missing from the encode method, and is necessary.

Author: nan-li

iOS_SDK/OneSignalSDK/OneSignalUser/Source/OSIdentityModel.swift

@@ -57,8 +57,10 @@ class OSIdentityModel: OSModel {
     }
 
     override func encode(with coder: NSCoder) {
-        super.encode(with: coder)
-        coder.encode(aliases, forKey: "aliases")
+        aliasesLock.locked {
+            super.encode(with: coder)
+            coder.encode(aliases, forKey: "aliases")
+        }
     }
 
     required init?(coder: NSCoder) {

iOS_SDK/OneSignalSDK/OneSignalUser/Source/OSPropertiesModel.swift

@@ -102,10 +102,12 @@ class OSPropertiesModel: OSModel {
     }
 
     override func encode(with coder: NSCoder) {
-        super.encode(with: coder)
-        coder.encode(language, forKey: "language")
-        coder.encode(tags, forKey: "tags")
-        // ... and more
+        tagsLock.locked {
+            super.encode(with: coder)
+            coder.encode(language, forKey: "language")
+            coder.encode(tags, forKey: "tags")
+            // ... and more
+        }
     }
 
     required init?(coder: NSCoder) {